Tension-releasing mechanism for sewing-machines



No. 62I,980. Patented Mar. 28, I899. F. I. STOCKWELL.

TENSION RELEASING MECHANISM FOR SEWING MACHINES.

(Application filed Mar. 15, 1898.)

(No Model.)

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FRED I. STOCKWELL, OF MALONE, NEW YORK.

SPECIFICATION forming part of Letters Patent No. 621,980, dated March28, 1899.

Application filed March 15, 1898.

To whom it may concern:

Be it known that I, FRED I. S'rooKwELL, a citizen of the United States,residing at Malone, county of Franklin, and State of New York, haveinvented a certain new and useful Improvement in Automatic Releases forThread-Tensions for Sewing-Machines, of which the following is aspecification.

My invention relates to a new and useful improvement in automaticreleases for threadtensions for sewing-machines, and has for its objectto provide a simple and effective means whereby the tension upon theupper thread may be relieved automatically when the presser-foot islifted for the shifting of the work from one point to another, thusavoidin g the necessity of having to release the tension by'hand or drawthe thread against the tension, which requires considerable strain uponthe thread, as well as deflects the needle, occasioning annoyance and"loss of time.

With these ends in view this invention consists in the details ofconstruction and combination of elements hereinafter set forth and thenspecifically designated by the claims.

In order that those skilled in the art to which this inventionappertains may understand how to make and use the same, the constructionand operation will now be described in detail, referring to theaccompanying drawings, forming a part of this specification, in whichFigure 1 is a rear elevation of a sewingma'chine of standard make havingmy improvement applied thereto, the same being connected with thetreadle or knee presserfoot lift mechanism; Fig. 2, an enlarged sec--tion of the tension, showing the same released by the pivoted lowerplate, the arm for operating this plate being shown in dotted lines;Fig. 3, a plan view of the tension with my improvement applied thereto;and Fig. 4, a section at the line m as of Fig. 1, showing the connectionbetween the lever for operating the presser-foot and the arm foroperating the tension.

In carrying out my invention as here embodied I form with or secure tothe pivoted tension-plate A an extension or arm B, which afterprojecting outward from the plate, as indicated at 0, runs parallel withthe machine-head and terminates in a flanged sec- Serial No. 673,943.(No model.)

tion D, forming a groove for the reception of the stud, as clearly shownin Fig. 4. The lever H is pivoted at J to the head of the machine and isconnected by the rod K to a suitable foot or knee treadle, whereby thislever may be operated without occupying the hands of the operator, as iswell understood. The opposite end of the lever H is connected by a linkL to the presser-foot bar M by the screw 0, passing through the slot P,thus when the treadle is operated the presser-foot is raised fromthework, thereby freeing the latter, so that it may be moved from point topoint as occasion may require, and when the presser is thus raised it isobvious that the post E will force the arm B upward, and in so doingswing the tensionplate A in such manner as to deflect the plate Q andfree the thread R, as clearly shown in Fig. 2. When the presser-foot andtension mechanism are in this position, it will be seen that the upperthread maybe as readily drawn from the-spool as the lower thread fromthe shuttle, thus avoiding the deflecting of the needle or the chafingof the upper thread in passing through the eye thereof under tension.

It is to be noted that the slot P provides for the ordinary movements ofthe presserbar without affecting the link or lever H, so that thepresser-foot may pass over work of varying thicknesses without in anywise affecting the tension, and this is of considerable importance,since should there be a rigid connection between the tension and thepresser foot or bar when said presser-foot is lifted to a considerableextent by quick ,work the tension would be released, and, as is wellknown, the tension is most needed when thick work is being operatedupon.

A further feature of my invention which is of considerable importance isthe fact that thereis no rigid connection between the post E and the arm13, as the latter simply rests upon the former, and therefore when it isnecessary to release the tension by hand independent of the treadle thismay be accomplished by forcing the arm upward.

One of the great advantages of my improvcment is the fact that it may beattached to any standard machine, requiring no alteration thereof, thusadapting it to machines of any use, and it is especially advantageousfor use in connection with machines which are operating upon certainclasses of worksuch as buttonholes, stitching on of buttons, binding,two-needle cylinder-machines, and tacking-machines, as in these classesof work the operator is constantly having to stop the Work at a givenpoint and shift it to another point, and in so doing thread must bedrawn through the needle with tension or released by hand, whereas by myimprovement the same is accomplished automatically when the presser-footis lifted.

Of course I do not Wish to be limited to the exact details ofconstruction here shown, as these may be varied to a certain extent without departing from the spirit of my invention.

Having thus fully described my invention, What I claim as new and usefulis 1. In combination with a presser-foot of a sewing-machine, alift-lever for operating the presser-foot, a post carried by the lever,a plate 2, a tension-plate having an arm whereby it is operated, saidarm having a flanged section fitting over the post and means foroperating the lifting-lever, as and for the purpose described.

2. In combination, a presser-foot, a lever, a link connecting the leverand presser-foot, a post carried by the lever, a plate 2, atension-plate, an arm formed with the tensionplate having a flangeembracing the post, said post being adjustable on the lever, as and forthe purpose described.

In testimony whereof I have hereunto affixed my signature in thepresence of two subscribing witnesses.

FRED I. STOCIUVELL.

Witnesses:

J. B. TWADDLE, JOHN LAW.

